Right now I'm thinking of draining the whole mess and making a new gravy but if there's a way to salvage what's already there I'd try it.
Before you pitch it, I'd consider cooking it even longer -- we're aiming for 'ragoût' (cooked to rags), not just your typical stew. We want the vegetables to completely disintigrate, until they're more a thickener for the stew, rather than indentifiable on their own.
You can then serve it over pasta, rice, or a baked potato.
If you'd prefer adding back in some vegetables for texture without further cooking of the meat ... I'd actually suggest roasting them in the oven, then mixing them in. Proper selection of vegetables can also be important -- a waxy potato (like a red potato) won't break down like a starchy (aka. flourly) potato (like a russet) will. If you're going to cook them in the stewing liquid, add tomatoes or a shot of vinegar into the liquid to prevent onions and potatoes from softening too much. Frozen peas or corn can add some quick texture (canned are typically mush, and might add to the metallic flavor).
As for the blandness issues, it's hard to say. If your basic salt and pepper aren't working, reach for other herbs & spices. You could try going heavy on the paprika and thyme to make it more like a goulish, or a blend of 'italian' spices to make it more like a ragù but beware of oregano which can have a metallic quality in large amounts. Sometimes alcohol can help, like a shot of sherry towards the end, or some wine, hard cider or beer earlier in the cooking process.
For both the blandness and metallic issues, vinegar or other acidic (eg, tomatoes but not canned) or sour (eg, serving with sour cream) notes might help.
... so, to summarize :
- Option 1 : cook longer, re-season, serve over rice/pasta/etc.
- Option 2 : re-season, add roasted vegetables and/or frozen peas or corn for texture.
- Add tomatoes, vinegar or sherry to brighten the flavors
- Serve w/ sour cream to mask metallic taste.